1. Field of the Invention
The present invention relates to a vibration type driving device in which a vibration element and a contact element brought into contact with the vibration element are moved relative to each other by vibration generated in the vibration element.
2. Related Background Art
A conventional vibration type driving device (vibration motor) is proposed in, e.g., Japanese Patent Application Laid-Open No. 5-252767. As shown in FIG. 6, this motor synthesizes the bending vibration generated by piezoelectric elements 12a and 12c and the expansion-shrinkage vibration generated by a stacked piezoelectric element 13 to generate elliptic motion in a frictional member 15. A driven element (contact element) 11 contacting the frictional member 15 is moved. The frictional member 15 is made of a steel material, while the driven element 11 is made of a ceramic material such as alumina.
In the above motor, the frictional member 15 contacts and receives an impact at the same position, while the contact position of the driven element 11 constantly changes. For this reason, the driven element 11 can be made of a ceramic poor in toughness and fatigue strength. When ceramic is used in a traveling wave vibration motor whose slide portion repeatedly receives impact, an alumina-based ceramic material tends to fail and any other ceramic material greatly abrades.